Sepsis is the tenth-leading cause of death in the United States and the second-leading cause of death in the intensive care unit (ICU). Sepsis kills over 215,000 Americans each year - more than breast cancer, lung cancer, and prostate cancer combined. Rapid identification and determination of antibiotic susceptibility is critical fo effective treatment of infected patients. Phase I successfully demonstrated the iSense system's ability to discriminate bacterial species and strain 4-fold faster than legacy methods identify species alone. In Phase I iSense also successfully demonstrated the ability to determine strain-specific susceptibility to antibiotic therapy more than 1 day faster than conventional practice. Phase II aims address application to clinical human specimens along with development of instruments and media appropriate for commercial use. The ultimate goal of this research is to develop and commercially deploy an automated blood culture system that can diagnose sepsis, identify the species and strain of the infecting organism, and determine antibiotic susceptibility all in less than 24 hours from the lab's receipt of primary specimen.